Switching control of accommodation: experimental and simulation responses to ramp inputs.
The irregular staircase appearance of the accommodation response to a ramp stimulus, slow movement of a target towards the subject's eye, suggests a switching between different states of control. Experiments and model simulations indicate that blur processing by retina and cortex underlies threshold triggering of the switch. The ON state consists of a fairly high gain, closed-loop control system that minimizes error. The OFF state provides for a quasi-open-loop state and a slow drift to a bias level, under the influence of a leaky integrator.
Sun
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Neurology and Telerobotics Unit, University of California, Berkeley 94720.
Stark
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D000065:Accommodation, Ocular / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D012815:Signal Processing, Computer-Assisted